User manual

DTS Broadcast PDH Microwave Digital Radio User Manual
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7.5 ODU configuration
A protected configuration typically consists of redundant IDUs and ODUs and a waveguide
coupler to connect the two ODUs to a single antenna port. If desired a second antenna may be used
instead of the waveguide coupler, providing protection against an antenna falling out of alignment. The
dual ODU/dual antenna configuration is required for Space Diversity systems. The following
descriptions assume all protected systems are configured with a single antenna and a waveguide
coupler.
7.6 Protected Mode
7.6.1 Hot Standby Protection Mode
The main and standby radios are tuned the same frequency. Transmitters of the off-line radio are
muted. When a fault is detected, the on-line terminal is muted, the standby terminal is unmuted, and
traffic is switched to the newly unmuted terminal. This system can be dual ODU/dual antenna
configuration or dual ODU/single antenna configuration.
7.6.2 Frequency Diversity Protection Mode
The main and standby radios are typically set up at least two channels apart to avoid interference.
Both radios are unmuted and ready to pass data. When a fault is detected on the active radio, the traffic
is switched to the stand-by radio. This system can be dual ODU/dual antenna configuration or dual
ODU/single antenna configuration.
7.6.3 Space Diversity Mode
The main and stand-by radios are set up in Hot Stand-by mode, but are connected to their own
antennas.
Both antennas, separated by a specific distance, are receiving the signal transmitted from the
on-line radio at the other end of the link. If a fault occurs in the receiving end of the link, the traffic is
switched to the stand-by radio without causing errors (hitless receive switching). As in Hot Stand-by
mode, a fault detected in the on-line transmitter causes that transmitter to mute and the stand-by radio
to un-mute.